Helmet

ABSTRACT

The invention relates to a helmet having an outer shell with an apex and having an inner envelope demarcated by a lower edge, the helmet further comprising an internal structure arranged within the inner envelope, the internal structure including a plurality of ribs, each rib extending from the apex to the lower edge.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon French Patent Application No. 13/01883, filed Aug. 5, 2013, the disclosure of which is hereby incorporated by reference thereto in its entirety, and the priority of which is claimed under 35 U.S.C. §119.

BACKGROUND

1. Field of the Invention

The invention relates to the field of helmets, such as sports helmets, including helmets intended for any of skiing, mountaineering, climbing, and cycling.

2. Background Information

Sports helmets typically comprise an outer shell and a layer forming an internal structure. The outer shell defines an inner envelope demarcated by a lower edge. The internal structure is housed in the inner envelope and defines a volume within which the user inserts his or her head. Generally, a comfort inner cap is interposed between the internal structure and the skull of the user.

The outer shell and internal structure combination protects the head of the user. This combination is intended to absorb impacts to the helmet and to prevent perforation or puncture of the protective arrangement. In addition to impact resistance, weight is an important factor affecting the performance of a helmet. Indeed, user comfort is closely related to the weight of the helmet. Thus, certain athletes do not use helmets because they find them to be too heavy. The weight of the helmet supported by the head has direct influence on the level of user fatigue, which is proportional to the time the helmet is worn. Consequently, the lighter the helmet, the better the sensations of the wearer and his/her athletic performance will be. Moreover, a lightweight helmet enables the user to have a greater sense of freedom and ease in head movements. In this case, the user no longer has the feeling of wearing a helmet.

Several solutions have been proposed to reduce the weight of helmets; such solutions generally providing to reduce the weight of the layer forming the internal structure. However, to maintain a satisfactory impact resistance, the material density cannot be overly reduced with a conventional construction, which consequently limits the reduction in weight.

Thus, there is a need for a construction that makes it possible to reduce the weight of a sports helmet significantly while maintaining satisfactory strength, particularly for impact absorption. Such is an object of the present invention.

SUMMARY

To this end, the invention provides a helmet comprising an outer shell having an apex and defining an inner envelope demarcated by a lower edge. The helmet also comprises an internal structure arranged within the inner envelope. The internal structure includes a plurality of ribs, each rib extending from the apex to the lower edge.

Because of this construction, shock absorption is largely provided by the ribs of the internal structure. Indeed, during impacts, the ribs deform by compressing or bending, which makes it possible to reduce the impact energy that is transmitted to the head of the user. By extending from the apex to the lower edge, the ribs have good damping properties.

A number of internal structures form a layer of the same material. This layer does not necessarily have a constant thickness but substantially covers the surface of the skull. By being formed of ribs, the internal structure is more recessed than conventional structures, which makes it possible to reduce the mass of the internal structure and therefore to limit the weight of the helmet. Alternatively, the space between two ribs may be filled with a material having very low density compared to the material of the ribs.

The arrangement of the ribs makes it possible to evenly distribute both the weight of the helmet during use and the energy transmitted to the head during impact.

In addition, the internal structure defines a free space between each pair of adjacent ribs for air flow, thereby improving ventilation and user comfort.

Optionally, the invention may have any of the following optional features, taken alone or in combination:

-   -   the ribs extend along a first direction, from the apex to the         lower edge and, along a second direction, from the outer shell         inward of a volume defined by the inner envelope;     -   each rib extends in a plane such that, at any point of the rib,         this plane is perpendicular to another plane that is tangent to         the inner envelope, at a right angle with that point;     -   each rib extends in a vertical plane when the helmet is worn         normally, without tilting of the head. Each rib has a main         direction of elongation extending from the apex to the lower         edge;     -   at least some, and in a particular embodiment all, of the ribs         conform to the shape of the inner envelope along a meridian         portion, a pole of which is the apex of the inner envelope;     -   at least some, and in a particular embodiment all, of the ribs         have an outer profile shaped to conform to the shape of the         inner envelope, and an inner profile shaped to conform to the         shape of the skull of the user. Alternatively, at least some,         and in a particular embodiment all, of the ribs have an outer         profile shaped to conform to the shape of the inner envelope,         and a discontinuous inner profile having cutouts and shaped to         take support on the head of the user only between two successive         cutouts;     -   at least some, and in a particular embodiment all, of the ribs         have a support zone adapted to be in support against the head of         the user. This support zone is a surface support zone. However,         a comfort inner cap can be interposed between the skull and the         shaped inner profile. The comfort inner cap can be formed of a         cushion, foam, and/or fabric;     -   the ribs are configured to take support on the head of the user,         on the one hand, and on the outer shell, on the other hand. The         ribs are thus arranged in the propagation path of the shocks         generated on the helmet;     -   the thickness (e) of at least some, and in a particular         embodiment all, of the ribs is less than or equal to its height         (h), the height (h) at a point of the rib being taken         perpendicular to the inner envelope in that point, and the         thickness (e) being taken along a direction perpendicular to the         height and perpendicular to a dimension along which the rib         extends mainly. In a particular embodiment, the thickness of the         rib is less than 0.8 times or, in a particular embodiment, less         than 0.6 times its height;     -   each rib has a height (h) between 1.0 cm and 5.0 cm or, in a         particular embodiment, between 1.0 cm and 3.5 cm, the height (h)         at a point of the rib being taken perpendicular to the inner         envelope and passing through that point. Each rib has a         thickness (e) between 0.5 cm and 3.0 cm or, in a particular         embodiment, between 0.6 cm and 1.0 cm, the thickness (e) at a         point of the rib being taken perpendicular to the main direction         of elongation of the rib. The thickness (e) of a rib corresponds         to the distance separating the two lateral surfaces of the rib;     -   each rib has a substantially constant thickness;     -   the helmet comprises a bonding layer affixing the internal         structure to the outer envelope. According to an embodiment, the         bonding layer connects two adjacent ribs of the internal         structure to one another. This keeps the ribs affixed to the         outer shell in the event of an impact. The ribs then absorb the         compression deformations over their entire height. In this case,         the helmet may have the following characteristics:         -   the bonding layer extends along each rib over a dimension at             least equal to half or, in a particular embodiment, at least             equal to two thirds, of the length of the rib, the length of             the rib being taken along the main dimension along which it             extends, that is to say, along the curve extending from the             apex towards the lower edge. According to an embodiment, the             bonding layer extends partially along each rib, from the             lower edge to the apex. According to an embodiment, the             bonding layer extends along each rib, over the entire length             of the rib;         -   the bonding layer conforms to the shape of the inner             envelope;         -   the bonding layer is continuous. According to a particular             embodiment, it covers the inner envelope in its entirety,             except for the ribs;         -   the bonding layer and the ribs define an outer envelope             shaped to conform to the shape of the inner envelope of the             outer shell. According to an embodiment, the outer envelope             forms a continuous surface, without relief, shaped to be             continuously in contact with the inner envelope. This             enables a better transmission of forces to the internal             structure during an impact;         -   the bonding layer has a smaller height than that of the             ribs. According to an embodiment, the height of the bonding             layer is then less than 0.8 times or, in a particular             embodiment, less than 0.6 times the height of the ribs. It             can be greater than eight millimeters, at any point;         -   the bonding layer is made of a material having different             properties than the constituent material of the ribs. It may             be a material of the same family, or a different material.             According to an embodiment, the bonding layer is made from a             material whose density is less than that of the material             forming the ribs. This makes the helmet lighter. According             to an embodiment, the density of the ribs is between 60             grams and 100 grams per liter. According to an embodiment,             the density of the bonding layer is between 10 grams and 100             grams per liter, and can be less than 60 grams per liter.     -   the material forming the ribs and/or the material forming the         bonding layer is expanded polystyrene, for example, which is         usually designated by the acronym EPS. It may also be expanded         polypropylene, which is usually designated by the acronym EPP.     -   at least one rib is formed by shaping a sheet between the two         lateral surfaces of the rib. For example, in the thickness of         the rib, the sheet may form corrugations, slots, zigzags, or         other repetitive patterns. The ribs may be made of paper or         cardboard;     -   the ribs of the internal structure have different materials         and/or densities;     -   the ribs of the internal structure have dimensional variations         and in particular different thicknesses or local cutouts in         their height. According to an embodiment, the ribs have an inner         profile with inner cutouts. The support line between the head         and the rib is therefore not continuous. This enables the ribs         to deform in bending and/or in rotation and to improve         ventilation of the helmet;     -   the ribs are evenly distributed around the periphery of the         lower edge;     -   the internal structure forms a plurality of sectors demarcated         by two adjacent ribs, the sectors being open in the area of the         lower edge;     -   the internal structure is a unitary, monolithic structure, and,         in a particular embodiment, obtained by injection of a material         forming the ribs;     -   the internal structure is an assembly of a plurality of separate         elements including the ribs and a common support, in which each         rib is assembled on a common support arranged in the area of the         apex. According to an embodiment, each rib includes a fixing         member adapted to cooperate with a complementary fixing member         carried by the support, the cooperation of the fixing members         carried by the rib and the support ensuring the affixing of the         rib on the support;     -   each rib extends between a first end arranged in the area of the         apex and a second end, a connecting band connecting all of the         second ends to one another. This enables good retention of the         free ends of the ribs. According to an embodiment, the second         ends extend to the lower edge, and the connecting band extends         over the entire periphery of the lower edge;     -   the inner envelope is a solid/continuous surface and has no         openings. According to another embodiment, the inner envelope         has openings for ventilation.

Other objects, features and advantages of the present invention will become apparent upon reviewing of the following description and accompanying drawings. It is understood that other advantages may be incorporated.

BRIEF DESCRIPTION OF DRAWINGS

The objects and characteristics, as well as the advantages of the invention will become more apparent from the detailed description of an embodiment thereof, which is illustrated by the following annexed drawings, in which:

FIG. 1 is a perspective view of an exemplary embodiment of a helmet according to the invention;

FIG. 2 is a perspective view of an internal structure portion for a helmet as that illustrated in FIG. 1, with a disassembled rib being shown;

FIG. 3 is a perspective view of an outer shell and an internal structure portion before assembly to form a helmet as that illustrated in FIG. 1;

FIG. 4 is a bottom view of the helmet of FIG. 1, before assembly of the straps.

FIG. 5 is a cross-sectional view of the helmet of FIG. 4 along the cross section V;

FIG. 6 is a cross-sectional view of the helmet of FIG. 4 along the cross section VI;

FIG. 7 is a cross-sectional view of the helmet of FIG. 4 along to the cross section VII;

FIG. 8 is a cross-sectional view of the same section as FIG. 7, of a helmet according to another embodiment, in which the ribs have particular shapes.

DETAILED DESCRIPTION

The drawings are given by way of examples and are not to be considered to limit the invention.

The helmet 1 according to the invention comprises an outer shell 100 having an apex 102, an outer surface turned outwards, and an inner surface 104 defining an inner envelope 101. The inner envelope 101 extends from the apex 102 to the lower edge 103 of the outer shell, and defines a volume for receiving an internal structure 200. FIG. 3 clearly illustrates the internal structure 200 prior to being inserted into the inner envelope 101. As described in detail below, the invention is not limited to the embodiments of the helmet in which the internal structure 200 is obtained separately from the outer shell 100 prior to being assembled in the latter.

Indeed, the invention extends to manufacturing methods in which the internal structure 200 is injected directly within a previously produced outer shell 100.

The internal structure 200 comprises a set of ribs 201. When the internal structure 200 is located in the outer shell 100, the ribs 201 extend between the apex 102 and the lower edge 103, that is to say, from the apex 102, or from a region of the apex, to the lower edge 103 or substantially to the lower edge. Each rib 201 has an outer profile 202 shaped to conform to the inner surface 104. In a particular embodiment, the outer shell 100 and internal structure 200 are shaped so that the outer profile 202 of each rib 201 is in contact with the inner surface 104 over the entire dimension along which the rib 201 extends.

Each rib 201 has an inner profile 203, or free surface, shaped to face and to conform to the shape of the skull of the user. A comfort inner cap, not shown, may be inserted between the ribs and the head of the user, thereby improving the wearing comfort.

Each outer 202 and inner 203 profile is curved.

Thus, the assembly formed by the laterally successive spaced-apart ribs 201 defines a hollow volume for receiving the head. This assembly thus forms a hollow dome or skeleton. Each rib 201 is in the form of an arch substantially extending from the apex 102 to a lower edge 103, thus forming a meridian, a pole of which is the apex 202 of the inner envelope 101.

According to a particular embodiment, at least some, and possibly all of the ribs 201, extend to the lower edge 103.

Each rib 201 extends mainly along a longitudinal curve following the curvature of the inner envelope 101. The rib 201 is characterized by a height “h” and a thickness “e”.

The height “h” may vary along the rib. It is defined along a direction perpendicular to the inner envelope 101 in the area of the measurement.

The thickness “e” is defined along a direction perpendicular to the height and the length of the rib corresponding to the longitudinal curve.

According to an embodiment, the thickness “e” is less than the height “h” of the rib 201. Thus, each rib 201 can easily deform in compression or in bending along its height in the event of an impact. The effective dimension for impact absorption is primarily its height. Its thickness may be reduced to limit the weight of the helmet 1, while enabling the helmet to maintain good overall impact resistance.

The cross section of the rib 201 along a plane perpendicular to the longitudinal curve is characterized by the height and thickness. The cross section may be rectangular, square, trapezoidal, or more generally polygonal.

According to an embodiment, the rib 201 extends along a vertical plane when the helmet 1 is worn on a non-tilted head. This orientation of the ribs provides good damping in the main impact configurations.

In the illustrated embodiment, the internal structure 200 comprises seventeen ribs 201. The geometry of the ribs varies, depending upon their location, so as to follow the inner envelope 101 and the morphology of the skull. In this example, the thickness of the ribs is constant and ranges between 0.5 cm and 3.0 cm or, in a particular embodiment, between 0.6 cm and 1.0 cm. The height varies between 1.0 cm and 5.0 cm or, in a particular embodiment, between 1.3 cm and 3.0 cm along each rib. Locally, the height depends on the shape of the outer shell. Therefore, these height values are not fixed. The smallest height can be close to the lower edge 103. The greatest height can be close to the middle of the length of the rib.

According to an embodiment, all of the ribs 201 have the same thickness. This makes it possible to facilitate the manufacture of the internal structure 200, because the ribs 201 can then be obtained by making a cutout 207 in the same plate, as descried in detail below.

According to another embodiment, the ribs 201 have different thicknesses. For example, greater thicknesses are provided in zones requiring reinforcement, or to ensure adequate strength of the helmet. The other ribs 201 may smaller thicknesses to reduce the weight of the helmet 1. The sizing of the ribs is important because it affects the impact absorption. Therefore, the ribs are sized so as to be able to damp either by direct compression or by bending/buckling of the rib, or by a combination of both phenomena. The sizing is adapted in the zones often that are biased during impacts, such as the forehead, the back of the head, or in particularly fragile zones such as the temples. The thickness should not be too small in order not to cause wearing discomfort.

Similarly, the distribution of the ribs 201 may be adapted to optimize the weight of the helmet 1, while maintaining satisfactory impact resistance. For example, the ribs 201 may be arranged so as to be closer to one another in sensitive zones (forehead, back of the head, temples) and more spaced apart in the other zones.

Alternatively, the ribs 201 are distributed evenly over the entire periphery of the lower edge 103.

According to an embodiment, the helmet 1 includes a binder provided for affixing the various ribs 201 to the outer shell 100. This binder forms a bonding layer 211 joining two adjacent ribs 201 as shown in FIGS. 1 and 4-8. This makes it possible to maintain the ribs 201 in position in relation to one another and on the outer shell 100. This also prevents the ribs from sliding or collapsing during impact, for example.

The bonding layer 211 irremovably fixes at least one rib 201 to the outer shell 100. This anchoring makes it possible to keep the internal structure continuously affixed to the outer shell. The helmet then has a monolithic, i.e., one-piece, construction. The internal structure is then non-removable.

Moreover, by being fixed, the ribs deform during impact so as to provide damping that is adapted to the normative need.

According to an embodiment not shown, the height of the bonding layer 211 is identical to those of the ribs 201. Thus, the ribs 201 and the bonding layer 211 define a second inner envelope adapted to conform to the shape of the skull of the user. In this embodiment, the bonding layer 211, along with the ribs, also participates in absorbing the impact.

According to an embodiment illustrated in FIGS. 1 and 4-8, the height of the bonding layer 211 is less than that of the ribs 201. Thus, the ribs 201 provide a space 214 between the ribs 201 and the skull of the user, which reduces the weight of the helmet 1 and improves ventilation.

According to this embodiment, the bonding layer 211 extends over the entire space between two adjacent ribs 201. Thus, this bonding layer 211 extends along the entire length of each rib 201. Thus, the inner surface 104 of the outer shell 100 is not visible when the internal structure 200 is located in the inner envelope 101. This makes it possible to reinforce the outer shell 100 and improve the helmet resistance to impact or perforation.

The height of the connecting layer 211 between the ribs is, in a particular embodiment, greater than eight millimeters at any point in order to ensure good retention and cohesion of ribs with respect to one another. Below this value, the ribs may collapse.

According to an embodiment, there may be zones with no bonding layer locally, in zones not likely to be biased and not affecting the strength of the internal structure. This makes it possible to further lighten the helmet.

According to an embodiment, the bonding layer 211 extends to the lower edge.

As illustrated in the drawing figures, in the immediate vicinity of a rib 201, the bonding layer 211 is provided to have an increasing height towards that rib 201. Thus, the bonding layer 211 forms a relief that can be also termed a weld seam 212. This makes it possible to reinforce the position of the rib 201 and the cohesion between ribs 201 and binder 211 by limiting the weight of the helmet 1. The weld seam 212 appears clearly in FIGS. 5 and 6.

According to an embodiment, and as illustrated in FIG. 5, the height of the bonding layer 211 varies along the rib 201. Thus, the height h1 in the vicinity of the lower edge 103 is greater than the height h2 located in the upper portion of the helmet 1. This makes it possible to limit the quantity of material and therefore the weight of the helmet 1, while reinforcing the zones that need to be reinforced. Moreover, this distribution remains compatible with an embodiment of the helmet by injection of the binder.

Alternatively, the height of the bonding layer 211 is uniform between the apex 102 and the lower edge 103.

According to an embodiment, the ribs 201 are made of EPS. This makes it possible to reduce the cost of the helmet 1. Alternatively, the ribs are made of EPP, a material having a higher elastic yield than EPS, which therefore enables the helmet to absorb stronger impacts before being altered. The helmet can thus be reused after sustaining certain limited impacts.

EPP and EPS also have the advantage of being hydrophobic. Therefore, they can be used without the addition of a sealing envelope.

A density between 60 g/l and 100 g/l can be selected for the ribs 201 made of EPS or EPP.

Alternatively, in particular embodiments, corrugated cardboard or paper, or rubber, is selected for the ribs 201. A watertight protection can also be provided for these embodiments to protect the ribs 201 from water.

Alternatively, rubber is selected for the ribs 201.

According to a particular embodiment, all of the ribs 201 are made of the same material and have the same density. Alternatively, certain ribs do not have the same density and/or are not made of the same material as other ribs. This makes it possible to adapt the strength and weight of the internal structure 200. The characteristics of the helmet can thus be adapted locally, for example by reinforcing the sensitive portions. This also makes it possible to optimize the weight of the helmet.

According to a particular embodiment, the material of the binder 211 is also made of EPP or EPS, without this being limiting.

Although the material of the ribs 201 and the material of the binder 211 are of the same type, a difference in density between these elements may be provided. For example, the ribs 201 can have a higher density than the binder 211 to ensure good impact absorption and good retention of the helmet 1 on the skull. In contrast, a binder 211 of lower density makes it possible to reduce the weight of the helmet 1. In this case, the density of the binder 211 is between 10 g/l and 60 g/l so as to be lower than the density of the ribs 201.

Alternatively, identical densities, between 60 g/l and 100 g/l, and, in a particular embodiment, identical materials are selected for the ribs 201 and the binder 211. In this embodiment, the bonding layer 211 can have a height significantly less than that of the ribs 201 to make the helmet 1 lighter.

Typically, the height of the bonding layer 211, on at least half of the length of the rib, is less than 70% of the height of the rib 201.

The invention has the advantage of being compatible with two techniques for manufacturing helmets.

The first technique, known as “in-mold” construction, includes the following. First, the outer shell 100 is made. For example, a plate made of polycarbonate or an equivalent material is heated. It can be a copolymer of acrylonitrile butadiene styrene (ABS), flax, carbon fibers or glass fibers. The plate is then deformed along a curvature. Then, the edges are cut. This outer shell is soft, very light, and resistant to perforation or puncture. Second, the outer shell 100 is inserted in a mold, and the same material is then injected within the outer shell to form both the internal structure 200 comprising the ribs 211 and the bonding layer 211. In this case, the internal structure 200 and the binder 211 form a molded monolithic element having great cohesion and strength. The helmet thus produced has a very good integrity between its constituent elements and is particularly light. Moreover, this embodiment makes it possible to reduce the assembly steps. One can provide to add a coating on the inner surface of the shell, before the second step, in order to improve the adhesion between the latter and the internal elements.

Alternatively, the inner portion is made by bi-injection, which enables use of a different material between the ribs and the binder.

According to an alternative embodiment, the previously made internal structure 200 is inserted into the outer shell 100 in the second step, as illustrated in FIG. 3. This subassembly 100 comprised of the outer shell and 200 and the internal structure is then inserted into the mold. Then, the binder 211 is injected to affix the internal structure 200 to the outer shell 100. Again, the helmet produced has very good integrity between its constituent elements and is particularly light. This embodiment includes an additional assembly step, compared to the previous embodiment. However, it allows for more possibilities in making of the internal structure 200, as described below.

A compatible second technique involves making the outer shell by injection rather than by deformation in in a first step. The outer shell is then more rigid, a little heavier, and has good strength and resistance to perforation or puncture. In a particular embodiment, the material used is acrylonitrile butadiene styrene (ABS). Alternatively, the other materials mentioned above can be provided for the outer shell 100.

The internal structure can be affixed to the outer shell by injection, in a manner similar to the previously described assemblies. Alternatively, the internal structure can be assembled to the inner shell by bonding or another technique, the binder being the adhesive element between the internal structure and the outer shell.

The internal structure 200 can be made separately.

According to an embodiment illustrated in FIG. 2, the internal structure 200 is made by the assembling of various ribs. Each rib has a first end 204 adapted to be arranged in the area of the apex 102. This first end 204 comprises a fixing member 206 for fixing the rib 201, either directly to other ribs or to an element forming a common support 210 for connecting all of the ribs 201 (as shown in FIG. 2).

In the latter embodiment, the support 210 has a body 213 in the form of a tube providing a space 214 to make the helmet 1 lighter. The tube cross section can be circular or oval to enable good distribution of forces on the ribs. Alternatively, the cross section is polygonal and/or solid. The drawing figures show that, once positioned, the ribs 201 define a housing 209 for receiving the support 210. This body 213 also comprises fixing members 215 complementary to the members 206 of the ribs 201. On the example shown, these complementary fixing members 215 form slots each shaped to receive a stud 216 carried by the first end 204 of the rib 201. In a particular embodiment, the upper and lower ends of the support 210 have slots over their entire periphery, and each of the first ends 204 of the ribs 201 has two studs or projections 216. The studs 216 of the same rib 201 are configured so that each is inserted into a slot cut in the upper and lower ends, respectively, of the body 213.

FIGS. 7 and 8 clearly illustrate the support 210 forming a common fixing element for all of the ribs 201. In these drawing figures, the thickness of the body section 213 appears in cross section in the recess formed between the two studs 216 of each rib 201. The common support 210 thus forms a keystone for the entire internal structure 200.

This embodiment has the advantage of being particularly easy to carry out because it does not require an injection mold. It suffices to cut ribs 201 using laser or water jet, and then assemble them to one another or to the common support 210. This type of cut is very easily modifiable and makes it possible to customize the shape of the ribs 201 easily and at low cost.

Therefore, the volume receiving the head of the user can easily be customized, for example to provide a broad range of helmets to fit a number of skull morphologies. Alternatively, or in combination, the outer profile can also easily be customized to offer a wide range of shapes for the shell.

Furthermore, this embodiment enables easy use of various materials to optimize the weight and strength of the helmet. For example, different materials may be used for the support 210 and the ribs 201. Also, different materials may be used for the ribs, typically depending upon their positioning around the skull, as mentioned above.

The binder is then positioned between the ribs 201 to form the bonding layer 211.

In particular embodiments, a structure or a resorbable material is provided to maintain the ribs 201 in position before and during injection of the bonding layer 211 between the ribs 201.

According to an embodiment illustrated in FIG. 8, openings 208 are provided in the ribs. In this example, these openings 208 are located in the vicinity of the inner surface 104 of the outer shell 100. They are typically located at a distance between 1.0 mm and 10 mm therefrom. Their diameter is greater than 3.0 mm, so that during injection, the bonding material 211 penetrates into the openings 208. When the bonding material 211 solidifies, it reinforces the cohesion between the ribs 201 and the bonding layer 211 located therebetween, thereby improving the strength of the helmet 1.

Furthermore, and irrespective of the helmet manufacturing technique, cutouts 207 can be provided on the inner profile 203 of the ribs 201. Thus, the inner profile 203 of the ribs does not form a line in continuous support with the skull. This makes it possible to increase the ventilation of the helmet 1; in particular, this enables the portions of the ribs 201 located between the cutouts 207 to deform in bending and/or in translation in order to improve the absorption of the forces transmitted from the outer shell 100 to the skull.

Typically, the depth of the cutout 207, measured along the same direction as the height “h” of the rib 201, is greater than 30% of the height of the rib in a zone with no cutout 207.

Once the internal structure has been made in the outer shell, the helmet is finalized by adding a strap. In a particular embodiment, a comfort inner cap is added between the skull and the ribs.

According to an embodiment, the helmet includes a connecting band connecting the ribs in the vicinity of their second ends 205, such as, in a particular embodiment, a connecting band having a width the same as the heights of the second ends 205 of the ribs. This ensures a better retention of the internal structure 200 on the outer shell 100. This also makes it possible to avoid lateral collapse of the second ends 205. In a particular embodiment, the connecting band is applied over the entire circumference of the inner envelope 101, and in a particular embodiment, in the area of the lower edge 103. In a particular embodiment, it is formed by the bonding material, during the same step for making of the bonding layer 211.

The invention is not limited to the embodiments described above and extends to all of the embodiments covered by the claims.

Lastly, at least because the invention is disclosed herein in a manner that enables one to make and use it to achieve various ones of the characteristics mentioned above in the disclosure of particular exemplary embodiments of the invention, the invention can be practiced in the absence of any additional element or additional structure that is not specifically disclosed herein. 

1. A helmet comprising: an outer shell comprising: an apex; a lower edge; and an inner envelope demarcated by the lower edge; an internal structure positioned within the inner envelope of the outer shell; the internal structure comprising a plurality of ribs, each of the plurality of ribs extending between the apex to the lower edge; and a bonding layer irremovably securing the internal structure to the outer shell.
 2. A helmet according to claim 1, wherein: the bonding layer is an injected bonding layer.
 3. A helmet according to claim 1, wherein: the plurality of ribs includes a pair of laterally successive and spaced-apart pair of ribs; and the bonding layer binds together at least the pair of laterally successive and spaced-apart pair of ribs.
 4. A helmet according to claim 1, wherein: the bonding layer has, at least in a transverse cross section of the helmet, a height less than a height of the ribs.
 5. A helmet according to claim 1, wherein: the bonding layer and the ribs are made of respectively different materials.
 6. A helmet according to claim 1, wherein: the bonding layer and at least some the plurality of ribs are made of materials having respectively different densities.
 7. A helmet according to claim 1, wherein: the plurality of ribs and/or the bonding layer are made of EPP or EPS.
 8. A helmet according to claim 1, wherein: the plurality of ribs is made of a material having a density between 60 and 60 g/l.
 9. A helmet according to claim 1, wherein: the bonding layer is made of a material having a density between 10 and 100 g/l.
 10. A helmet according to claim 1, wherein: all of the plurality of ribs do not have an identical density and/or are not made of an identical material.
 11. A helmet according to claim 10, wherein: each of at least some of the plurality of ribs has a surface having a shape of the inner envelope of the outer shell, each of the surfaces extending along a meridian extending through the apex.
 12. A helmet according to claim 1, wherein: each of at some of the plurality of ribs has a thickness (e) less than or equal to its height.
 13. A helmet according to claim 1, wherein: at least one of the plurality of ribs has an inner profile designed to face a head of a wearer in a use position when the helmet is worn by the wearer; the inner profile comprises a plurality of cutouts extending between the apex and the lower edge of the outer shell.
 14. A helmet according to claim 1, wherein: the internal structure comprises an assembly of separate pieces, each of the plurality of ribs forming a separate one of the pieces.
 15. A helmet according to claim 1, wherein: each of the plurality of ribs has a first end and a second end; the first end is arranged at the apex of the outer shell; and a connecting strip interconnects all of the second ends.
 16. A helmet according to claim 1, wherein: each of the plurality of ribs has a respective free surface designed to face and to be engageable with a head of a wearer in a use position of the helmet when the helmet is worn by the wearer.
 17. A helmet according to claim 16, wherein: the internal structure is an innermost structure of the helmet.
 18. A helmet according to claim 1, wherein: each of the plurality of ribs has a respective free surface designed to face a head of a wearer in a use position of the helmet when the helmet is worn by the wearer; and no additional structure of the helmet extends laterally across the free surfaces of the plurality of ribs at respective lengthwise intermediate portions of the plurality of ribs.
 19. A helmet according to claim 1, wherein: each of at least some of the plurality of ribs has a height that varies between the apex and the lower edge.
 20. A helmet according to claim 1, wherein: each of at least some of the plurality of ribs has a greatest height at a lengthwise intermediate portion between the apex and the lower edge. 